This invention relates to reducing steps of working component parts and of assembling them in manufacturing ball joints. It relates also to an improved ball joint in which the open marginal edge of a housing need not be turned or rolled toward a closing plate put inside the marginal edge, and the preload applied to the ball head of a ball stud can be adjusted properly.
A conventional ball joint comprises a housing having a circular cylindrical internal surface, a ball stud with its ball head contained in the housing, a synthetic resin or sintered alloy bearing member supporting the ball head in the housing. A closing plate is put inside the open end of the housing and is fastened by folding the marginal open edge of the housing towards the closing plate by means of rolling and the like. The closing plate thus fastened presses the bearing member to its enclosed assembled position directly or through a suitable resilient member such as a piece rubber or a spring. The marginal open edge of the housing must be machined precisely into a thin form which is designed for the more reliable fastening of the closing plate and for the proper value of the preload. Furthermore, in order to give the ball head the proper preload, it is necessary to provide a shoulder portion to receive the closing plate on the internal surface of the open end portion of the housing, or to fasten the closing plate under a pressure to press it against the bearing member. Namely, the working and assembling of the housing requires not only many steps but also precision of high degree, and complicated machinery improved for exclusive use are necessary.